The present invention relates basically to the field of after treatment of exhaust gases. More precisely, the present invention relates, according to a first aspect, to a particle filter arrangement for filtering exhaust gases of an internal combustion engine, in particular of a diesel internal combustion engine, having an inlet and an outlet, with at least one particle filter being arranged in the flow path of the exhaust gases between the inlet and outlet, with the exhaust gases being conducted in a line, with the line having a first section or segment in which the exhaust gases are conducted substantially in the direction of the outlet, with the line also having a second section or segment in which the exhaust gases are conducted substantially in the direction of the inlet. According to a second aspect, the present invention relates to a particle filter arrangement for filtering exhaust gases of an internal combustion engine, in particular of a diesel internal combustion engine, having an inlet and an outlet, with a deflecting element for changing the direction of the exhaust-gas flow being provided in the flow path of the exhaust gases between the inlet and the outlet. According to a third aspect, the present invention relates to a particle filter arrangement for filtering exhaust gases of an internal combustion engine, in particular of a diesel internal combustion engine, having an inlet and an outlet. According to a fourth aspect, the present invention relates to a method for filtering exhaust gases of an internal combustion engine, in particular of a diesel internal combustion engine, by means of a particle filter arrangement having an inlet and an outlet.
Exhaust gases which are generated by internal combustion engine or industrial processes generally contain potentially harmful constituents such as for example hydrocarbons (HC), carbon monoxide (CO), nitrogen oxide (NOx) and in particular also particle constituents such as for example particulate matter. Such constituents must be converted into harmless or at least less harmful constituents in order to reduce the quantity of harmful substances which are discharged to the atmosphere. The exhaust gases are therefore conventionally subjected to a catalytic treatment and/or a filtering process.
Also fundamentally known in the prior art are catalytic converters which serve to remove harmful constituents such as for example SOx and NOx from the exhaust gases. In addition, a catalytic converter also has the effect of increasing the temperature of exhaust gases, which can in turn assist the breakdown of soot particles.
In diesel engines, there is the basic problem that soot particles (CO) in particular are contained in the exhaust gases. To remove these exhaust gases, particle filters are known. The soot particles are generated in particular by the addition of additives to the fuel. Although the particle filter can remove the soot from the exhaust gases, it does however have the problem that it becomes blocked or fully laden if too many soot particles are stored in it. At a correspondingly high temperature (above approximately 400° C.), however, the CO is broken down, and a fully-laden filter can therefore be regenerated at such a temperature. It is therefore particularly important for the temperature of the exhaust gases to be as high as possible before and during the filtering, and in particular also for the temperature in the filter to be as high as possible, such that the “ignition temperature” is reached.
Here, it is particularly important that the installation space of the overall particle filter arrangement and of the particle filter itself is as small as possible, and that a high temperature is reached as quickly as possible such that the auto-ignition effect starts, since otherwise the filter becomes blocked too quickly and for example a motor vehicle is no longer operational. In particular in the case of a driving pattern in which the vehicle is driven for only a few minutes per day (“fetching rolls in the morning”), the filter can become ever more fully-laden with soot particles without a sufficiently high temperature for burning off the soot being reached, so that after some time, the motor is no longer operational and the filter must be exchanged. How fast a required high temperature is reached is therefore also particularly important. These are known problems in the prior art, which are associated with the cold start of an engine (with a correspondingly cold catalytic converter) and with “cold exhaust gases” as are discharged by a diesel engine.
The temperatures of the exhaust gases are fundamentally dependent on the type of diesel engine used and, in the case of motor vehicles, are of course dependent on the respective type. Normally, in a motor vehicle, the temperatures of the exhaust gases are supposed to be between 150 and 210° C. In the case of a naturally-aspirated engine, the temperatures of the exhaust gases are approximately 280° C. and, with a turbocharger, 350° C. The problem of the full loading of a required particle filter is therefore significantly less serious in a naturally-aspirated engine or turbocharged engine, since the outlet temperatures of the exhaust gases are already correspondingly high. For normal diesel engines, the full loading or blockage of the particle filter is in practice a serious problem which the prior art cannot sufficiently remedy.